Downburst winds happen as rain-cooled air from a collapsing thunderstorm hits the ground and spreads out fiercely in all directions.
Unlike a tornado or dust devil, downburst winds do not rotate. They are directed outward from the point where they hit the ground.
Dry downbursts are associated with thunderstorms that contain very little rain, while wet downbursts are created by thunderstorms that bring a lot of rain.
On most stormy monsoon days, thunderstorm activity will end in the late evening. This is the most common time for a downburst to occur, resulting in severe wind gusts that can cause extensive damage.
The term microburst refers to a downburst over one small, localized area. Specifically, an area that is 2.5 miles in diameter or smaller.
Downbursts winds can be as strong as hurricane force winds and also create vertical wind shear which is dangerous to aircraft.
They don’t happen very often, but they do happen fast. Telephone poles, wooden power poles, trees and other objects can be knocked over instantly.
On August 14, 1996, a wind gust of 115 mph was recorded at the Deer Valley Airport and the resulting damage exceeded $160 million.
